Topological dereliction in polymers

An exactly solvable toy model is introduced to illustrate the entropie frustrations and their thermodynamic consequences in self-ordering systems.     

Resource planning and bandwidth allocation in hybrid fiber–coax residential networks

The introduction of new high bandwidth services such as video-on-demand by cable operators will put a strain on existing resources. It is important for cable operators to know how many resources to commit to the network to satisfy customer demands. In this paper, we develop models of voice and video traffic to determine the effect of demand growth on hybrid fiber–coax networks. We obtain a set of guidelines that network operators can use to build out their networks in response to increased demand. We begin with one type of traffic and generalize to an arbitrary number of high-bandwidth constant bit rate (CBR) like services to obtain service blocking probabilities. We consider the effect of supporting variable bit rate (VBR) packet-switched traffic in addition to CBR services. These computations help us to determine how cable networks would function under various conditions (i.e., low, medium, and heavy loads). We also consider how the growth rate of the popularity of such services would change over time, and how this impacts network planning. Our findings will help cable operators estimate how much bandwidth they need to provision for a given traffic growth model and connection blocking requirement.     

Structure‐Guided Design of Thiazolidine Derivatives as Mycobacterium tuberculosis Pantothenate Synthetase Inhibitors

The pantothenate biosynthetic pathway is essential for the persistent growth and virulence of Mycobacterium tuberculosis (Mtb) and one of the enzymes in the pathway, pantothenate synthetase (PS, EC: 6.3.2.1), encoded by the panC gene, has become an appropriate target for new therapeutics to treat tuberculosis. Herein, we report nanomolar thiazolidine inhibitors of Mtb PS developed by a rational inhibitor design approach. The thiazolidine compounds were discovered by using energy‐based pharmacophore modelling and subsequent in vitro screening, which resulted in compounds with a half maximal inhibitory concentration (IC₅₀) value of (1.12±0.12) μM . These compounds were subsequently optimised by a combination of modelling and synthetic chemistry. Hit expansion of the lead by chemical synthesis led to an improved inhibitor with an IC₅₀ value of 350 nM and an Mtb minimum inhibitory concentration (MIC) of 1.55 μM . Some of these compounds also showed good activity against dormant Mtb cells.     

Elemental Analogues of Graphene: Silicene,Germanene, Stanene,and Phosphorene

The fascinating electronic and optoelectronic properties of free‐standing graphene has led to the exploration of alternative two‐dimensional materials that can be easily integrated with current generation of electronic technologies. In contrast to 2D oxide and dichalcogenides, elemental 2D analogues of graphene, which include monolayer silicon (silicene), are fast emerging as promising alternatives, with predictions of high degree of integration with existing technologies. This article reviews this emerging class of 2D elemental materials – silicene, germanene, stanene, and phosphorene – with emphasis on fundamental properties and synthesis techniques. The need for further investigations to establish controlled synthesis techniques and the viability of such elemental 2D materials is highlighted. Future prospects harnessing the ability to manipulate the electronic structure of these materials for nano‐ and opto‐electronic applications are identified.     

Stretchable and Tunable Microtectonic ZnO‐Based Sensors and Photonics

The concept of realizing electronic applications on elastically stretchable “skins” that conform to irregularly shaped surfaces is revolutionizing fundamental research into mechanics and materials that can enable high performance stretchable devices. The ability to operate electronic devices under various mechanically stressed states can provide a set of unique functionalities that are beyond the capabilities of conventional rigid electronics. Here, a distinctive microtectonic effect enabled oxygen‐deficient, nanopatterned zinc oxide (ZnO) thin films on an elastomeric substrate are introduced to realize large area, stretchable, transparent, and ultraportable sensors. The unique surface structures are exploited to create stretchable gas and ultraviolet light sensors, where the functional oxide itself is stretchable, both of which outperform their rigid counterparts under room temperature conditions. Nanoscale ZnO features are embedded in an elastomeric matrix function as tunable diffraction gratings, capable of sensing displacements with nanometre accuracy. These devices and the microtectonic oxide thin film approach show promise in enabling functional, transparent, and wearable electronics.     

Parametric studies on a metal hydride based hydrogen storage device

In this paper, a two-dimensional computational investigation of coupled heat and mass transfer process in an annular cylindrical hydrogen storage device filled with _MmNi4.6Al0.4${\mathrm{MmNi}}_{4.6}{\mathrm{Al}}_{0.4}$ is presented using a commercial software FLUENT 6.1.22. Hydrogen storage performance of the device is studied by varying the operating parameters such as hydrogen supply pressure and absorption temperature. Further, the effects of various bed parameters such as hydride bed thickness and overall heat transfer coefficient on the storage performance of the device are also studied. The average temperature of the hydriding bed and hydrogen storage capacity at different supply pressures showed good agreement with the experimental data reported in the literature. It is observed that as the hydriding process is initiated, the absorption of hydrogen increases rapidly and then it slows down after the temperature of the hydride bed increases due to the heat of the reaction. At any given absorption temperature, the hydrogen absorption rate and hydrogen storage capacity are found to increase with the supply pressure. The variation in the hydrogen absorption capacity, rate of reaction and temperature profiles at different supply pressures from 5 to 35 bar in steps of 5 bar are presented. Further, the effects of overall heat transfer coefficients from 750 to 1250 W/m² K and cooling fluid temperatures from 288 to 298 K on hydrogen storage capacity are also investigated. It is shown that the heat transfer rate enhances the hydriding rate by accomplishing a rapid reaction. At the supply condition of 35 bar and 298 K, _MmNi4.6Al0.4${\mathrm{MmNi}}_{4.6}{\mathrm{Al}}_{0.4}$ stores about 13.1 g of hydrogen per kg of alloy.     

Effects of salt and ammonium hydroxide on the quality of ground buffalo meat

The objective of this study was to evaluate the effects of ammonium hydroxide (AH) and sodium chloride on the quality of ground buffalo meat patties. Ground buffalo meat was treated with distilled water (control), 0.5% v/w AH, 1.0% v/w AH, 2.0% v/w AH and 1.0% w/w sodium chloride was added for all the samples. Treatment with AH increased (P<0.05) the pH and water holding capacity (WHC) of ground buffalo meat patties during storage relative to their controls. Hunterlab a* (redness) and chroma values increased (P<0.05) and hue decreased (P<0.05) in all AH treated samples in comparison to controls during storage. Ammonium hydroxide significantly (P<0.05) inhibited metmyoglobin formation compared to control after 3rd day of storage. There was a significant (P<0.05) reduction in thiobarbituric acid reactive substances (TBARS) values in all AH treated samples compared to control throughout storage. These results indicate the potential antioxidant and myoglobin redox stabilizing effect of AH in ground buffalo meat patties.     

Cue-based networking

In this paper we present a new approach called cue-based networking that uses hints or cues about the physical environment to optimize networked application behavior. We define the notion of cues and describe how cues can be obtained using wireless sensor networks as the underlying platform. We identify both the research and system challenges that need to be addressed to realize benefits of the approach under a target application of video delivery over IP networks. In the process, we identify key challenges of wireless sensor networks, namely timeliness and robustness. We design an adaptive algorithm that balances the tradeoff between them satisfying both timeliness and robustness requirements. Through an implementation of the video delivery application using the proposed algorithm in a real home environment, we highlight the practical benefits of the proposed approach.     

Nanoscale Characterization of Energy Generation from Piezoelectric Thin Films

We report on the use of nanoindentation to characterize in situ the voltage and current generation of piezoelectric thin films. This work presents the controlled observation of nanoscale piezoelectric voltage and current generation, allowing accurate quantification and mapping of force function variations. We characterize both continuous thin films and lithographically patterned nano­islands with constrained interaction area. The influence of size on energy generation parameters is reported, demonstrating that nanoislands can exhibit more effective current generation than continuous films. This quantitative finding suggests that further research into the impact of nanoscale patterning of piezoelectric thin films may yield an improved materials platform for integrated microscale energy scavenging systems.